Two materials on one object
You can perform a "double side material" node setup with the geometry node (selecting the backfacing option). The following image presents half a cube where the exterior is grass and the interior is gravel. The backfacing option uses the same UVmap but shows the texture for the other side of the faces, so from your steps, you can ignore step 8 and step 9. The same technique is used to create double sided pages, in a book or similar.